.block {
  display: block;
}

.flex {
  display: flex;
  /* 设置主轴：横向排列（默认） */
  &.d-row {
    flex-direction: row;
  }
  /* 设置主轴：竖向排列 */
  &.d-col {
    flex-direction: column;
  }
  /* 主轴居中 */
  &.main-center {
    justify-content: center;
  }
  &.main-start {
    justify-content: flex-start;
  }
  &.main-end {
    justify-content: flex-end;
  }
  &.main-between {
    justify-content: space-between;
  }
  &.main-around {
    justify-content: space-around;
  }

  /* 侧轴居中 */
  &.sub-center {
    align-items: center;
  }
  &.sub-start {
    align-items: flex-start;
  }
  &.sub-end {
    align-items: flex-end;
  }
  &.sub-baseline {
    align-items: baseline;
  }
  &.sub-stretch {
    align-items: stretch;
  }
  &.sub-normal {
    align-items: normal;
  }
  &.sub-flex-start {
    align-items: flex-start;
  }
  &.sub-flex-end {
    align-items: flex-end;
  }
}

.grid {
  display: grid;
}
